I. Field of the Invention
This invention relates to apparatus for comminuting foodstuffs. Specifically, the present invention relates to a machine for shredding or grating a block of cheese or the like and to a blade useful therefor.
II. Description of the Prior Art
Typical machines for shredding or grating cheese employ a circular metal blade with a plurality of apertured cutting teeth formed integrally therein. Although specific reference will be had herein to shredding it is to be understood that whether the foodstuff is shredded or grated is dependent on the specific cutting teeth formed in the blade. The problems encountered by the prior art, and the principles of the invention are interchangeable with respect to shredding or grating. Accordingly, it is to be understood that whether shredding or grating is referred to herein, either or both may be used.
The blade is either mounted about its periphery to a hub which is mounted to a motor shaft or the blade may be mounted in the center directly to the motor shaft or an extension thereof. As the blade rotates under the influence of the motor shaft, the cutting teeth cooperate to provide a circular cutting area having its axis of rotation coincident with the blade's axis of rotation.
A commonly encountered problem is that the central area of the blade (concentric with the axis of rotation) provides little, if any, comminuting or shredding action. Hence, the central region becomes a "dead zone" which can impede the progress of the shredding action. As a consequence, the central dead zone has typically been avoided.
The standard approach to avoiding the central dead zone is to present the face of the block of cheese to less than the full cutting area at any one time. Typically, the block of cheese was thus presented to the blade to one side of the central dead zone resulting in an active cutting area of approximately 50% or less of the available cutting area of the blade. Hence, only a portion of the blade is shredding the cheese at any one time resulting in lengthy periods of operation to shred a predetermined amount of cheese, say a five pound block.
An additional problem encountered by avoiding the dead zone is that the blade may be too easily stalled or stopped during cutting. It is a known principal that to stop or slow a spinning disc requires application of less pressure against the circumference of the disc then at the center thereof. By avoiding the dead zone, more of the cheese is presented nearer the circumference of the blade. As a result, care has to be exercised to not force the block of cheese against the blade with too much pressure. Hence, shredding or grating pressure must be relatively light necessitating longer cutting operation and resulting in wasted labor. Also, even slight pressure would tend to slow or stall the blade thereby slowing the cutting operation as well as causing the electric motor driving the blade to fail prematurely.
An even further problem is that while the blade face may be large enough to permit the full face of a typical five pound block of cheese to be presented to it, the active cutting area is smaller than the available cutting area of the blade. Hence, the active cutting area typically is not sufficiently large to handle the face of an uncut five pound block of cheese. Accordingly, to shred the cheese without encountering a dead zone may require that the block of cheese be sliced into smaller chunks thereby resulting in further labor costs and handling of the food. Otherwise, where the full cutting surface of the blade is presented with cheese, the dead zone acts to retard progress of the cheese into the blade resulting in an unnecessarily long shredding operation.
A further consequence of presenting cheese to the dead zone is that greater pressure is needed to force the block of cheese into the blade than where no dead zone is encountered. As shown in U.S. Pat. No. 4,002,298 to Latora, machines for comminuting a block of cheese typically move the cheese horizontally against a vertically mounted blade. The shredded (or grated) cheese then falls due to gravity from behind the blade and out of the machine. Thus, no movement of the block of cheese towards the blade occurs without some externally applied force. Were the blade to be mounted horizontally and the cheese thus lowered vertically against the blade, gravity would provide some of the force necessary to push the cheese into the blade. Many rotatable shredders and graters in which the blade is manually rotated, operate in that manner. Some automatic comminuting devices are similarly constructed. However, for commercial purposes, where large amounts of cheese must be handled in a short period of time, the benefits of using a horizontally mounted blade are minimized due to rapid build up or agglomeration of shredded cheese below the blade. As the cheese builds up, the area below the blade, and the blade itself, may become clogged thereby retarding the shredding action. Also, the machine may have to be stopped periodically to remove the built-up clumps of cheese thereby slowing down the operation and resulting in further handling of the cheese.